When three pipes fill a pool, they can finish in 12 hours. two of the pipes can finish in 18 hours if they are working together. how long would it take a third pipe to fill the pool on its own?

3 pipes take 12 hours
⇒ In 1 hour, the 3 pipes can fill 1/12 of the pool

2 of the pipes take 18 hours
⇒ in 1 hour, the 2 pipes can fill 1/18 of the pool

In 1 hour, the third pipe alone can fill :



Time needed :



----------------------------------------------------------------------------------------
It will take 36 hours for the third pipe to fill the pool.
----------------------------------------------------------------------------------------